AG3340 is a novel inhibitor of selected matrix metalloproteinases (MMPs) designed using knowledge of the X-ray crystal structures of recombinant human MMPs. AG3340 was chosen for development based on its relative selectivity for gelatinase-A, stromelysin-1 and collegenase-3. It is theorized that specific inhibition of these enzymes will result in optimal inhibition of tumor growth, invasion and metastasis while limiting the potential for toxicity inherent in broad inhibition of MMPs. The primary objectives of this study are the following: (1) Evaluate the safety tolerance of AG3340 administered orally to patients with advanced cancer; (2) determine the maximum tolerated dose and dose-limiting toxicities of AG3340; (3) assess the pharmacokinetics of AG3340 and assess the potential of AG3340 for inhibition of the hepatic enzyme CYP2D6; and (4) document any antitumor effects induced by AG3340.